page 33

Edit 0 6 …
Aim: How do we use a geometric sequence to solve problems? (This formula is not on the Regents Reference Sheet)

At the end of this lesson, you will be able to...

  1. define what is meant by a geometric sequence and its common ratio
  2. determine whether a sequence is a geometric, sequence, an arithmetic sequence, or neither
  3. determine the common ration, r, for the nth term of a geometric sequence
  4. discover the formula for the nth term of a geometric sequence
  5. explain how to find a specified term of a geometric sequence
  6. solve numeric, algebraic, and verbal problems using the geometric sequence formula

Here are some questions for you to copy into your notebooks and answer as you watch the videos.

  1. What is a geometric sequence?
  2. How do you determine if a sequence is a geometric sequence?
  3. Write the formula for a geometric sequence.



Video 1

Video 2


Classwork:
1. Is the sequence 4, 12, 36, 108, 324,...a geometric sequence? How do you know? (Ans: Yes, there is a common ratio of 3)
2. What is the 10th term of the sequence 4, 12, 36, 108, 324...? (Ans: 78732)
3. Find the four geometric means between 5 and 1215. (Ans: 15, 45, 135, and 405. The common ratio is 3


Homework: Answer numbers 3 - 41 in multiples of 3

GeoSquence.JPG

Answers:

A-GeoSequence.JPG

Journal entry: How can you tell if a sequence is geometric? Compare and contrast an arithmetic sequence with a geometric sequence.